A popular approach to building web applications includes combining content from more than one source into an integrated experience. Such combinations may be referred to as “mashups.” For example, a mashup of a web application, such as GOOGLE Maps, with another web application containing images from a natural disaster, can enhance the experience of both types of web applications.
Some web applications can store private user data on behalf of the user. For example, GOOGLE GMAIL stores e-mail messages, PICASA stores images, and GOOGLE Maps stores personalized maps. Many web applications do not permit the sharing of private user data with third parties, which may limit a mashup designer's ability to construct a mashup when private user data is involved.
When the use of private user data is permitted in third party applications, a user may receive a request to authorize the use. The user may receive this request multiple times if the user uses different computing devices to access a third party application that incorporates the user's private data. Additionally, the user may receive multiple requests to authorize use of the user's private data if the requested use varies from previously authorized uses.